aboutsummaryrefslogtreecommitdiffstats
path: root/src/svm/svm_fifo.h
blob: 619d60934296616fc7e565c1229b55bb722f107f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
/*
 * Copyright (c) 2016-2019 Cisco and/or its affiliates.
 * Copyright (c) 2019 Arm Limited
 * Copyright (c) 2010-2017 Intel Corporation and/or its affiliates.
 * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
 * Inspired from DPDK rte_ring.h (SPSC only) (derived from freebsd bufring.h).
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef __included_ssvm_fifo_h__
#define __included_ssvm_fifo_h__

#include <vppinfra/clib.h>
#include <vppinfra/vec.h>
#include <vppinfra/pool.h>
#include <vppinfra/format.h>
#include <vppinfra/rbtree.h>

/** Out-of-order segment */
typedef struct
{
  u32 next;	/**< Next linked-list element pool index */
  u32 prev;	/**< Previous linked-list element pool index */

  u32 start;	/**< Start of segment, normalized*/
  u32 length;	/**< Length of segment */
} ooo_segment_t;

#define SVM_FIFO_TRACE 			(0)
#define OOO_SEGMENT_INVALID_INDEX 	((u32)~0)
#define SVM_FIFO_INVALID_SESSION_INDEX 	((u32)~0)
#define SVM_FIFO_INVALID_INDEX		((u32)~0)
#define SVM_FIFO_MAX_EVT_SUBSCRIBERS	7

enum svm_fifo_tx_ntf_
{
  SVM_FIFO_NO_TX_NOTIF = 0,
  SVM_FIFO_WANT_TX_NOTIF = 1,
  SVM_FIFO_WANT_TX_NOTIF_IF_FULL = 2,
};

typedef struct
{
  u32 offset;
  u32 len;
  u32 action;
} svm_fifo_trace_elem_t;

typedef struct svm_fifo_chunk_
{
  u32 start_byte;
  u32 length;
  struct svm_fifo_chunk_ *next;
  u8 data[0];
} svm_fifo_chunk_t;

typedef enum svm_fifo_flag_
{
  SVM_FIFO_F_SIZE_UPDATE = 1 << 0,
  SVM_FIFO_F_MULTI_CHUNK = 1 << 1,
} svm_fifo_flag_t;

typedef struct _svm_fifo
{
  CLIB_CACHE_LINE_ALIGN_MARK (shared_first);
  u32 size;			/**< size of the fifo */
  u32 nitems;			/**< usable size(size-1) */
  u8 flags;			/**< fifo flags */
  svm_fifo_chunk_t *start_chunk;/**< first chunk in fifo chunk list */
  svm_fifo_chunk_t *end_chunk;	/**< end chunk in fifo chunk list */
  svm_fifo_chunk_t *new_chunks;	/**< chunks yet to be added to list */
  rb_tree_t chunk_lookup;

    CLIB_CACHE_LINE_ALIGN_MARK (shared_second);
  volatile u32 has_event;	/**< non-zero if deq event exists */

  u32 master_session_index;
  u32 client_session_index;
  u8 master_thread_index;
  u8 client_thread_index;
  u32 segment_manager;
  u32 segment_index;
  u32 ct_session_index;		/**< Local session index for vpp */
  u32 freelist_index;		/**< aka log2(allocated_size) - const. */
  i8 refcnt;			/**< reference count  */
  struct _svm_fifo *next;	/**< next in freelist/active chain */
  struct _svm_fifo *prev;	/**< prev in active chain */

    CLIB_CACHE_LINE_ALIGN_MARK (consumer);
  u32 head;			/**< fifo head position/byte */
  svm_fifo_chunk_t *head_chunk;	/**< tracks chunk where head lands */
  svm_fifo_chunk_t *ooo_deq;	/**< last chunk used for ooo dequeue */
  volatile u32 want_tx_ntf;	/**< producer wants nudge */
  volatile u32 has_tx_ntf;

    CLIB_CACHE_LINE_ALIGN_MARK (producer);
  u32 tail;			/**< fifo tail position/byte */
  u32 ooos_list_head;		/**< Head of out-of-order linked-list */
  svm_fifo_chunk_t *tail_chunk;	/**< tracks chunk where tail lands */
  svm_fifo_chunk_t *ooo_enq;	/**< last chunk used for ooo enqueue */
  ooo_segment_t *ooo_segments;	/**< Pool of ooo segments */
  u32 ooos_newest;		/**< Last segment to have been updated */
  volatile u8 n_subscribers;
  u8 subscribers[SVM_FIFO_MAX_EVT_SUBSCRIBERS];

#if SVM_FIFO_TRACE
  svm_fifo_trace_elem_t *trace;
#endif

  svm_fifo_chunk_t default_chunk;
} svm_fifo_t;

typedef enum
{
  SVM_FIFO_FULL = -2,
} svm_fifo_err_t;

typedef struct svm_fifo_segment_
{
  u8 *data;
  u32 len;
} svm_fifo_segment_t;

#if SVM_FIFO_TRACE
#define svm_fifo_trace_add(_f, _s, _l, _t)		\
{							\
  svm_fifo_trace_elem_t *trace_elt;			\
  vec_add2(_f->trace, trace_elt, 1);			\
  trace_elt->offset = _s;				\
  trace_elt->len = _l;					\
  trace_elt->action = _t;				\
}
#else
#define svm_fifo_trace_add(_f, _s, _l, _t)
#endif

u8 *svm_fifo_dump_trace (u8 * s, svm_fifo_t * f);
u8 *svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose);

/* internal function */
static inline void
f_load_head_tail_cons (svm_fifo_t * f, u32 * head, u32 * tail)
{
  /* load-relaxed: consumer owned index */
  *head = f->head;
  /* load-acq: consumer foreign index (paired with store-rel in producer) */
  *tail = clib_atomic_load_acq_n (&f->tail);
}

/* internal function */
static inline void
f_load_head_tail_prod (svm_fifo_t * f, u32 * head, u32 * tail)
{
  /* load relaxed: producer owned index */
  *tail = f->tail;
  /* load-acq: producer foreign index (paired with store-rel in consumer) */
  *head = clib_atomic_load_acq_n (&f->head);
}

/* producer consumer role independent */
/* internal function */
static inline void
f_load_head_tail_all_acq (svm_fifo_t * f, u32 * head, u32 * tail)
{
  /* load-acq : consumer foreign index (paired with store-rel) */
  *tail = clib_atomic_load_acq_n (&f->tail);
  /* load-acq : producer foriegn index (paired with store-rel) */
  *head = clib_atomic_load_acq_n (&f->head);
}

/* internal function */
static inline u32
f_free_count (svm_fifo_t * f, u32 head, u32 tail)
{
  return (f->nitems + head - tail);
}

/* internal function */
static inline u32
f_cursize (svm_fifo_t * f, u32 head, u32 tail)
{
  return (f->nitems - f_free_count (f, head, tail));
}

/* used by consumer */
static inline u32
svm_fifo_max_dequeue_cons (svm_fifo_t * f)
{
  u32 tail, head;
  f_load_head_tail_cons (f, &head, &tail);
  return f_cursize (f, head, tail);
}

/* used by producer*/
static inline u32
svm_fifo_max_dequeue_prod (svm_fifo_t * f)
{
  u32 tail, head;
  f_load_head_tail_prod (f, &head, &tail);
  return f_cursize (f, head, tail);
}

/* use producer or consumer specific functions for perfomance.
 * svm_fifo_max_dequeue_cons (svm_fifo_t *f)
 * svm_fifo_max_dequeue_prod (svm_fifo_t *f)
 */
static inline u32
svm_fifo_max_dequeue (svm_fifo_t * f)
{
  u32 tail, head;
  f_load_head_tail_all_acq (f, &head, &tail);
  return f_cursize (f, head, tail);
}

/* used by producer */
static inline int
svm_fifo_is_full_prod (svm_fifo_t * f)
{
  return (svm_fifo_max_dequeue_prod (f) == f->nitems);
}

/* use producer or consumer specific functions for perfomance.
 * svm_fifo_is_full_prod (svm_fifo_t * f)
 * add cons version if needed
 */
static inline int
svm_fifo_is_full (svm_fifo_t * f)
{
  return (svm_fifo_max_dequeue (f) == f->nitems);
}

/* used by consumer */
static inline int
svm_fifo_is_empty_cons (svm_fifo_t * f)
{
  return (svm_fifo_max_dequeue_cons (f) == 0);
}

/* used by producer */
static inline int
svm_fifo_is_empty_prod (svm_fifo_t * f)
{
  return (svm_fifo_max_dequeue_prod (f) == 0);
}

/* use producer or consumer specific functions for perfomance.
 * svm_fifo_is_empty_cons (svm_fifo_t * f)
 * svm_fifo_is_empty_prod (svm_fifo_t * f)
 */
static inline int
svm_fifo_is_empty (svm_fifo_t * f)
{
  return (svm_fifo_max_dequeue (f) == 0);
}

static inline u8
svm_fifo_is_wrapped (svm_fifo_t * f)
{
  u32 head, tail;
  f_load_head_tail_all_acq (f, &head, &tail);
  return head % f->size > tail % f->size;
}

/* used by producer*/
static inline u32
svm_fifo_max_enqueue_prod (svm_fifo_t * f)
{
  u32 head, tail;
  f_load_head_tail_prod (f, &head, &tail);
  return f_free_count (f, head, tail);
}

/* use producer or consumer specfic functions for perfomance.
 * svm_fifo_max_enqueue_prod (svm_fifo_t *f)
 * add consumer specific version if needed.
 */
static inline u32
svm_fifo_max_enqueue (svm_fifo_t * f)
{
  u32 head, tail;
  f_load_head_tail_all_acq (f, &head, &tail);
  return f_free_count (f, head, tail);
}

static inline int
svm_fifo_has_event (svm_fifo_t * f)
{
  return f->has_event;
}

static inline u8
svm_fifo_has_ooo_data (svm_fifo_t * f)
{
  return f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX;
}

/**
 * Sets fifo event flag.
 *
 * Also acts as a release ordering.
 *
 * @return 1 if flag was not set.
 */
always_inline u8
svm_fifo_set_event (svm_fifo_t * f)
{
  /* return __sync_lock_test_and_set (&f->has_event, 1) == 0;
     return __sync_bool_compare_and_swap (&f->has_event, 0, 1); */
  return !clib_atomic_swap_rel_n (&f->has_event, 1);
}

/**
 * Unsets fifo event flag.
 *
 * Also acts as an acquire barrier.
 */
always_inline void
svm_fifo_unset_event (svm_fifo_t * f)
{
  clib_atomic_swap_acq_n (&f->has_event, 0);
}

svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
void svm_fifo_init (svm_fifo_t * f, u32 size);
/**
 * Grow fifo size by adding chunk to chunk list
 *
 * If fifos are allocated on a segment, this should be called with
 * the segment's heap pushed.
 *
 * @param f	fifo to be extended
 * @param c 	chunk or linked list of chunks to be added
 */
void svm_fifo_add_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c);
void svm_fifo_free (svm_fifo_t * f);

int svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
			     const u8 * copy_from_here);
int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
				  u32 required_bytes, u8 * copy_from_here);
int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);

int svm_fifo_peek (svm_fifo_t * f, u32 offset, u32 max_bytes, u8 * copy_here);
int svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes);
void svm_fifo_dequeue_drop_all (svm_fifo_t * f);
int svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs);
void svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_segment_t * fs);
void svm_fifo_init_pointers (svm_fifo_t * f, u32 head, u32 tail);
void svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf);
void svm_fifo_overwrite_head (svm_fifo_t * f, u8 * data, u32 len);
void svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber);
void svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber);
format_function_t format_svm_fifo;

/**
 * Max contiguous chunk of data that can be read
 */
always_inline u32
svm_fifo_max_read_chunk (svm_fifo_t * f)
{
  u32 head, tail;
  u32 head_idx, tail_idx;
  f_load_head_tail_cons (f, &head, &tail);
  head_idx = head % f->size;
  tail_idx = tail % f->size;
  return tail_idx > head_idx ? (tail_idx - head_idx) : (f->size - head_idx);
}

/**
 * Max contiguous chunk of data that can be written
 */
always_inline u32
svm_fifo_max_write_chunk (svm_fifo_t * f)
{
  u32 head, tail;
  u32 head_idx, tail_idx;
  f_load_head_tail_prod (f, &head, &tail);
  head_idx = head % f->size;
  tail_idx = tail % f->size;
  return tail_idx >= head_idx ? (f->size - tail_idx) : (head_idx - tail_idx);
}

/**
 * Advance tail pointer
 *
 * Useful for moving tail pointer after external enqueue.
 */
always_inline void
svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 bytes)
{
  ASSERT (bytes <= svm_fifo_max_enqueue_prod (f));
  /* load-relaxed: producer owned index */
  u32 tail = f->tail;
  tail += bytes;
  /* store-rel: producer owned index (paired with load-acq in consumer) */
  clib_atomic_store_rel_n (&f->tail, tail);
}

always_inline u8 *
svm_fifo_head (svm_fifo_t * f)
{
  /* load-relaxed: consumer owned index */
  return (f->head_chunk->data
	  + ((f->head % f->size) - f->head_chunk->start_byte));
}

always_inline u8 *
svm_fifo_tail (svm_fifo_t * f)
{
  /* load-relaxed: producer owned index */
  return (f->tail_chunk->data
	  + ((f->tail % f->size) - f->tail_chunk->start_byte));
}

static inline void
svm_fifo_add_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
{
  f->want_tx_ntf |= ntf_type;
}

static inline void
svm_fifo_del_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
{
  f->want_tx_ntf &= ~ntf_type;
}

static inline void
svm_fifo_clear_tx_ntf (svm_fifo_t * f)
{
  /* Set the flag if want_tx_notif_if_full was the only ntf requested */
  f->has_tx_ntf = f->want_tx_ntf == SVM_FIFO_WANT_TX_NOTIF_IF_FULL;
  svm_fifo_del_want_tx_ntf (f, SVM_FIFO_WANT_TX_NOTIF);
}

static inline void
svm_fifo_reset_tx_ntf (svm_fifo_t * f)
{
  f->has_tx_ntf = 0;
}

static inline u8
svm_fifo_needs_tx_ntf (svm_fifo_t * f, u32 n_last_deq)
{
  u8 want_ntf = f->want_tx_ntf;

  if (PREDICT_TRUE (want_ntf == SVM_FIFO_NO_TX_NOTIF))
    return 0;
  else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF)
    return 1;
  else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF_IF_FULL)
    {
      u32 max_deq = svm_fifo_max_dequeue_cons (f);
      u32 nitems = f->nitems;
      if (!f->has_tx_ntf && max_deq < nitems
	  && max_deq + n_last_deq >= nitems)
	return 1;

      return 0;
    }
  return 0;
}

always_inline u8
svm_fifo_n_subscribers (svm_fifo_t * f)
{
  return f->n_subscribers;
}

u32 svm_fifo_number_ooo_segments (svm_fifo_t * f);
ooo_segment_t *svm_fifo_first_ooo_segment (svm_fifo_t * f);

always_inline ooo_segment_t *
svm_fifo_newest_ooo_segment (svm_fifo_t * f)
{
  if (f->ooos_newest == OOO_SEGMENT_INVALID_INDEX)
    return 0;
  return pool_elt_at_index (f->ooo_segments, f->ooos_newest);
}

always_inline void
svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
{
  f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
}

always_inline u32
ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos, u32 tail)
{
  return ((pos - tail) % f->size);
}

always_inline u32
ooo_segment_distance_to_tail (svm_fifo_t * f, u32 pos, u32 tail)
{
  return ((tail - pos) % f->size);
}

always_inline u32
ooo_segment_offset_prod (svm_fifo_t * f, ooo_segment_t * s)
{
  u32 tail;
  /* load-relaxed: producer owned index */
  tail = f->tail;

  return ooo_segment_distance_from_tail (f, s->start, tail);
}

always_inline u32
ooo_segment_length (svm_fifo_t * f, ooo_segment_t * s)
{
  return s->length;
}

always_inline ooo_segment_t *
ooo_segment_get_prev (svm_fifo_t * f, ooo_segment_t * s)
{
  if (s->prev == OOO_SEGMENT_INVALID_INDEX)
    return 0;
  return pool_elt_at_index (f->ooo_segments, s->prev);
}

always_inline ooo_segment_t *
ooo_segment_next (svm_fifo_t * f, ooo_segment_t * s)
{
  if (s->next == OOO_SEGMENT_INVALID_INDEX)
    return 0;
  return pool_elt_at_index (f->ooo_segments, s->next);
}

#endif /* __included_ssvm_fifo_h__ */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */